Heater Craft leaking hot air when off

[Dale777]

On my R27, I've noticed a lot of hot air leaking from the Heater Craft vent below the helm step, even when the Heater Craft selector knob is turned to OFF. I don't know if this is a new problem or not, but on my current extended cruise from Ft. Myers Beach to North Palm Beach across the Okeechobee Waterway it became really noticeable in the hot weather.

Is there a valve that the Selector Knob turns on/off or is it a baffle? What should I be checking for and where should I look?

 

[Irish Mist]

Dale
The cooling system circulates through the heater all the time The fan just passes air over the fins to disperse the heat better.. If it becomes an issue you would need to hook up a bypass so there is no hot coolant going through the heater.. Shouldn't be too complicated to do .
Hope this helps .. Mine is the same and might look at it later when it gets warm here again

 

[knotflying]

Dale,
Irish mist is correct. You don't have a problem. I get the same hot air while underway. In the winter months it's kind of nice to hang your feet over the edge and warm up your feet. A shutoff valve it the best way to deal with this, but a piece of cardboard behind the vent works well when you don't want heat in warmer weather. Just make sure you take it out in the winter.

 

[Irish Mist]

Be careful shutting it off as you need to maintain the return to the engine. On mine the coolant goes from the engine through the water heater, then through the Heater Craft and back to the engine. You would need to divert it after the water heater to loop back to the engine, bypassing the heater craft, Quite simple, just need to keep the loop to the engine.

 

[knotflying]

Be careful shutting it off as you need to maintain the return to the engine.

I am not sure if these lines are in series with the cooling system or run parallel off the system and the water circulates through natural convection. If they run parallel then closing it off won't be an issue without a bypass. I looked at my diagrams from my Mack Boring class and can't determine whether they are parallel or in series. Perhaps Howard Roland can ask this question at his Mack Boring class and confirm or maybe someone else knows for sure.

 

[Osprey]

The Ranger-27 “Closed Engine Cooling System” diagram I have shows a circuit from a fitting on the engine to the water heater then the cabin heater and back to the engine (series circuit). This would be much like the heater system in a car with a second heater series added to the car circuit. So one could use a single turn off but both the water heater and the cabin heater would be “off line”. A better method would be to add a by-pass after the water heater (“short circuit the cabin heater water line”) plus a turn off between the bypass and the cabin heater.

 

[Osprey]

Perhaps a point I did not make clear in my above post is the heaters' loop is essentially in parallel with the main engine cooling system. Closing off part or all of the heater line would have little or no effect on the ability of the engine to maintain the correct engine operating temperature.

 

[Dale777]

Thanks for all the comments about this topic. Temporarily, I've attached cardboard to the OUTSIDE of the vent. Expecting to attach the cardboard to the inside of the vent, I removed the 4 screws to the vent, thinking the vent cover only would remove, but the vent cover is attached directly to the heater radiator. Longer term, I will fabricate a piece of black painted metal to attach to the vent cover with some type of quick disconnect screws. Bypassing the flow of hot water to the heater is a greater project that I'm not sure is worth the trouble for me.

 

[Todd]

I am not at my boat right now so I don't remember if this is a metal or plastic grill. If it is metal you can make a nice cover out of the magnetic material they use for magnetic signs. It is available in letter size sheets at staples or office depot and if you need a larger piece you can get it a t a sign shop. Works great on metal grills.